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Types of Soils

While conducting baseline studies as an Environmental Monitor, you will need to conduct soil samples, in order to determine the type of the soil in a project area.

To begin sampling, you need to create a soil profile. A soil profile is basically a 2-dimensional section of soil, this can be seen in a soil pit with dimensions in the ballpark of a 1×1 meter hole. To create a soil profile, you simply need to dig a soil pit, using your shovel to create a clean edge, where the measurements are made.

In the top soil horizon, known as the Humus layer, you can usually find a variety of horizons, such as the ‘L’, ‘H’ and ‘F’ horizons. The ‘L’ horizon is the litter horizon of soil, which is a loose and identifiable horizon, comprised of recently fallen pieces of plants and animals. The ‘F’ horizon is the folic or fermented horizon – this horizon has recognizable plant remains that have turned brown or black, usually with fungi. The ‘H’ layer, also known as the humic horizon which is made up of brown or black plant remains that are well decayed and is not possible to recognize distinct plants. The ‘H’ layer is usually the bottom few centimeters of a humus layer.

When checking out the layers in a soil pit, you will be analyzing what is a called the mineral horizons. In this, the top of the mineral soil layer is classified as the ‘A’ horizon. This is the interface where the humus layer and the mineral soil begin. This layer has the most organic matter and soil life. This layer loses minerals through washing out of minerals into the layers below it. The next level of the soil pit will show the ‘B’ horizon, also known as the subsoil. Here illuviation occurs, where the minerals from the ‘A’ soils horizon wash down into it and enrich the soil. Below this layer is the ‘C’ horizon, which is usually unaltered parent material with no additions or losses in terms of mineral content.